The 1993 World Trade Center bombing occurred on February 26, 1993, when a truck bomb was detonated below the North Tower of the World Trade Center in New York City. The 1,500 lb (680 kg) urea nitrate–hydrogen gas enhanced device was intended to knock the North Tower (Tower One) into the South Tower (Tower Two), bringing both towers down and killing 250,000 people. It failed to do so, but did kill six people and injured 1,042.

The attack was planned by a group of conspirators including Ramzi Yousef, Mahmud Abouhalima, Mohammad Salameh, Nidal A. Ayyad, Abdul Rahman Yasin and Ahmad Ajaj. They received financing from Khaled Shaikh Mohammed, Yousef's uncle. In March 1994, four men were convicted of carrying out the bombing: Abouhalima, Ajaj, Ayyad and Salameh. The charges included conspiracy, explosive destruction of property and interstate transportation of explosives. In November 1997, two more were convicted: Yousef, the mastermind behind the bombings, and Eyad Ismoil, who drove the truck carrying the bomb.

Planning and organization

Ramzi Yousef, who was born as Abdul Basit Mahmoud Abdul Karim in Kuwait, spent time at Al-Qaeda training camps in Afghanistan, before beginning in 1991 to plan a bombing attack within the United States. Yousef's uncle Khalid Shaikh Mohammed Ali Fadden, who later was considered the principal architect of the September 11 attacks, gave him advice and tips over the phone, and funded him with a US$660 wire transfer.

Yousef arrived in the United States on September 1, 1992, traveling with Ahmed Ajaj from Pakistan, though both sat apart on the flight and acted as though they were traveling separately. Ajaj tried to enter with a Swedish passport, though it had been altered and thus raised suspicions among INS officials at John F. Kennedy International Airport. When officials put Ajaj through secondary inspection, they discovered bomb making instructions and other materials in his luggage, and arrested him. The name Abu Barra, an alias of Mohammed Jamal Khalifa, appeared in the manuals. Yousef tried to enter with a false Iraqi passport, claiming political asylum. Yousef was allowed into the United States, and was given a hearing date.

Yousef set up residence on Nicole Pickett Avenue[citation needed] in Jersey City, New Jersey, traveled around New York and New Jersey and called Sheik Omar Abdel Rahman, a controversial blind Muslim cleric, via cell phone. After being introduced to his co-conspirators by Abdel Rahman at the latter's Al-Farooq Mosque in Brooklyn, Yousef began assembling the 1,500 lb (680 kg) urea nitrate–hydrogen gas enhanced device for delivery to the WTC. He ordered chemicals from his hospital room when injured in a car crash – one of three accidents caused by Salameh in late 1992 and early in 1993.

El Sayyid Nosair, one of the blind sheik's men, was arrested in 1991 for the murder of Rabbi Meir Kahane. According to prosecutors, "the Red" Mahmud Abouhalima, also convicted in the bombing, told Wadih el Hage to buy the .357 caliber revolver used by Nosair in the Kahane shooting. In the initial court case in NYS Criminal Court Nosair was acquitted of murder but convicted of gun charges. (In a related and followup case in Federal Court, he was convicted). Dozens of Arabic bomb-making manuals and documents related to terrorist plots were found in Nosair's New Jersey apartment, with manuals from Army Special Warfare Center at Fort Bragg, North Carolina, secret memos linked to Joint Chiefs of Staff, and 1,440 rounds of ammunition. (Lance 2004 26)

Yousef's view of the attack

According to the journalist, Yousef mailed letters to various New York newspapers just before the attack, in which he claimed he belonged to 'Liberation Army, Fifth Battalion'. These letters made three demands: an end to all US aid to Israel, an end to US diplomatic relations with Israel, and a demand for a pledge by the United States to end interference "with any of the Middle East countries' interior affairs." He stated that the attack on the World Trade Center would be merely the first of such attacks if his demands were not met. In his letters Yousef admitted that the World Trade Center bombing was an act of terrorism, but that this was justified because "the terrorism that Israel practices (which America supports) must be faced with a similar one."

The attack

Image of the procession of rescue vehicles responding to the 1993 World Trade Center bombing. One World Trade Center is on the far right of the frame.

Ramzi Yousef and a Jordanian friend, Eyad Ismoil, drove a yellow Ryder van into Lower Manhattan, and pulled into the public parking garage beneath the World Trade Center around noon. Yousef ignited the 20-foot fuse, and fled. Twelve minutes later, at 12:17:37 pm, the bomb exploded in the underground garage, generating an estimated pressure of 150,000 psi. The bomb opened a 30-m (98 ft) wide hole through four sublevels of concrete. The detonation velocity of this bomb was about 15,000 ft/s (4.5 km/s).

The bomb instantly cut off the center's main electrical power line, knocking out the emergency lighting system. The bomb caused smoke to rise up to the 93rd floor of both towers, including through the stairwells which were not pressurized. With thick smoke filling the stairwells, evacuation was difficult for building occupants and led to many smoke inhalation injuries. Hundreds were trapped in elevators in the towers when the power was cut, including a group of 17 kindergartners, on their way down from the South Tower observation deck, who were trapped between the 35th and 36th floors for five hours.

Also as a result of the loss of electricity most of New York City's radio and television stations lost their over-the-air broadcast signal for almost a week, with television stations only being able to broadcast via cable and satellite via a microwave hookup between the stations and three of the New York area's largest cable companies, Cablevision, Comcast, and Time Warner Cable. Telephone service for much of Lower Manhattan was also disrupted.

Altogether, six people were killed and 1,042 others were injured, most during the evacuation that followed the blast. The towers did not collapse, according to Yousef's plan, but the explosion did damage the garage badly. Nevertheless, had the van been parked closer to the WTC's poured concrete foundations, Yousef's plan might have succeeded. Yousef escaped to Pakistan several hours after the bombing.

Yousef had left Jersey City much earlier in the morning, thus questions linger as to why he waited to noon to attack when the parking area was much less crowded. Conspirator Mahmud Abouhalima later stated that the original plan was to attack the United Nations headquarters earlier in the morning. Author Simon Reeve theorized that something went wrong, such as Yousef encountering too much security, and the target was changed to be the World Trade Center.

Yousef was assisted by Iraqi bomb maker Abdul Rahman Yasin, who helped assemble the complex 1,310 pounds (590 kg) bomb, which was made of a urea nitrate main charge with aluminum, magnesium and ferric oxide particles surrounding the explosive. The charge used nitroglycerine, ammonium nitrate dynamite, smokeless powder and fuse as booster explosives. Three tanks of bottled hydrogen were also placed in a circular configuration around the main charge, to enhance the fireball and afterburn of the solid metal particles. The use of compressed gas cylinders in this type of attack closely resembles the 1983 Beirut barracks bombing 10 years earlier. Both of these attacks used compressed gas cylinders to create fuel-air and thermobaric bombs that release more energy than conventional high explosives. According to testimony in the bomb trial, only once before the 1993 attack had the FBI recorded a bomb that used urea nitrate.

The Ryder van used in the bombing had 295 cubic feet (8.4 m3) of space, which would hold up to a 2,000 pounds (910 kg) of explosives. However, the van was not filled to capacity. Yousef used four 20 ft (6 m) long fuses, all covered in surgical tubing. Yasin calculated that the fuse would trigger the bomb in twelve minutes after he had used a cigarette lighter to light the fuse.

Yousef wanted the smoke to remain in the tower, therefore catching the public eye by smothering people inside, killing them slowly. He anticipated Tower One collapsing onto Tower Two after the blast.

There remains a popular belief that there was cyanide in the bomb, which is reinforced by Judge Duffy's statement at sentencing, "[y]ou had sodium cyanide around, and I’m sure it was in the bomb." However, the bomb's true composition was not able to be ascertained from the crime scene and Robert Blitzer, a senior FBI official who worked on the case, stated that there was "no forensic evidence indicating the presence of sodium cyanide at the bomb site." Furthermore, Yousef is said only to have considered adding cyanide to the bomb, and to have regretted not doing so in Peter Lance's book 1000 Years for Revenge.

Investigation

Though the cause of the blast was not immediately known, with some suspecting a transformer explosion, agents and bomb technicians from the ATF, FBI, and the NYPD quickly responded to the scene. The magnitude of the explosion was far beyond that of a transformer explosion.

In the days after the bombing, investigators surveyed the damage and looked for clues. While combing through the rubble in the underground parking area, a bomb technician located some internal component fragments from the vehicle that delivered the bomb. A vehicle identification number (VIN), found on a piece from an axle, gave investigators crucial information that led them to a Ryder truck rental outlet in Jersey City. Investigators determined that the vehicle had been rented by Mohammad Salameh, one of Yousef's co-conspirators. Salameh had reported the van stolen, and when he returned on March 4, 1993, to get his deposit back, authorities arrested him.

Salameh's arrest led police to the apartment of Abdul Rahman Yasin in Jersey City, New Jersey, which Yasin was sharing with his mother, in the same building as Ramzi Yousef's apartment. Yasin was taken to FBI headquarters in Newark, New Jersey, and was then released. The next day, he flew back to Iraq, via Amman, Jordan. Yasin was later indicted for the attack, and in 2001 he was placed on the initial list of the FBI Most Wanted Terrorists, on which he remains today. He disappeared before the U.S. coalition invasion, Operation Iraqi Freedom, in 2003. In March 1994, Salameh, Nidal Ayyad, Mahmud Abouhalima and Ahmad Ajaj were each convicted in the World Trade Center bombing. In May 1994, they were sentenced to life imprisonment.

The capture of Salameh and Yasin led authorities to Ramzi Yousef's apartment, where they found bomb-making materials and a business card from Mohammed Jamal Khalifa. Khalifa was arrested on December 14, 1994, and was deported to Jordan by the INS on May 5, 1995. He was acquitted by a Jordanian court and lived as a free man in Saudi Arabia until his death in 2007.

Aftermath

Memorial

Deaths in the 1993 bombing

1. Monica Smith, age 35, a secretary, who was seven months pregnant, was in her office checking time sheets in the B-2 level.

2. Robert (Bob) Kirkpatrick, age 61, a locksmith, was eating lunch in a room next to Smith's office.

5. John DiGiovanni, age 45, a dental products salesperson, was parking in the underground garage.

6. Wilfredo Mercado, age 37, a receiving agent for Windows on the World restaurant, was checking in deliveries.

A granite memorial fountain honoring the six victims of the bombing was designed by Elyn Zimmerman and dedicated in 1995 on Austin J. Tobin Plaza, directly above the site of the explosion. It contained the names of the six people who were killed in the attack as well as an inscription that read:

"On February 26, 1993, a bomb set by terrorists exploded below this site. This horrible act of violence killed innocent people, injured thousands, and made victims of us all."

The fountain was destroyed with the rest of the World Trade Center during the September 11 attacks. A recovered fragment from the 1993 bombing memorial with the text "John D", from bombing victim John DiGiovanni, is being used as the centerpiece of a new memorial honoring the victims of both the 1993 and 2001 attacks.

FBI involvement

In the course of the trial it was revealed that the FBI had an informant, a former Egyptian army officer named Emad Salem. Salem claims to have informed the FBI of the plot to bomb the towers as early as February 6, 1992. Salem's role as informant allowed the FBI to quickly pinpoint the conspirators out of hundreds of possible suspects.

Salem, initially believing that this was to be a sting operation, claimed that the FBI's original plan was for Salem to supply the conspirators with a harmless powder instead of actual explosive to build their bomb, but that the FBI chose to use him for other purposes instead. He secretly recorded hundreds of hours of telephone conversations with his FBI handlers.

Diplomatic Security Service (DSS) involvement

Aftermath of the bombing, photographed by DSS agents

Although the FBI received the credit, Diplomatic Security Service special agents actually found and arrested Ramzi Ahmed Yousef, the architect of the 1993 World Trade Center bombing. Special Agents Bill Miller and Jeff Riner were given a tip by an associate of Ramzi Yousef about his location. In coordination with the Pakistani Inter-Services Intelligence (ISI), DSS and ISI arrested Yousef. Security ranged for the World Trade from WTC security guards to car barriers which would not allow cars to enter certain areas. The New York Port Authority was to govern as the main security for the World Trade buildings. All packages were scanned at various checkpoints then sent up to the proper addressee. After his arrest, Ramzi Yousef is alleged to have said to investigators "this is only the beginning."

Allegations of Iraqi involvement

In October 2001 in a PBS interview, former CIA Director James Woolsey claimed that Ramzi Yousef worked for Iraqi intelligence. He suggested the grand jury investigation turned up evidence pointing to Iraq that the Justice Department "brushed aside." But Neil Herman, who headed the FBI investigation, noted "The one glaring connection that can't be overlooked is Yasin. We pursued that on every level, traced him to a relative and a location, and we made overtures to get him back." However, Herman says that Yasin's presence in Baghdad does not mean Iraq sponsored the attack: "We looked at that rather extensively. There were no ties to the Iraqi government." CNN terrorism analyst Peter L. Bergen writes, "In sum, by the mid-'90s, the Joint Terrorism Task Force in New York, the F.B.I., the U.S. Attorney's office in the Southern District of New York, the C.I.A., the N.S.C., and the State Department had all found no evidence implicating the Iraqi government in the first Trade Center attack."

Claims of direct Iraqi involvement come from Laurie Mylroie of the American Enterprise Institute, with the claims rejected by other experts. Peter Bergen has called her a "crackpot" who claimed that "Saddam was not only behind the '93 Trade Center attack, but also every anti-American terrorist incident of the past decade, from the bombings of U.S. embassies in Kenya and Tanzania to the leveling of the federal building in Oklahoma City to September 11 itself."[26] Daniel Benjamin, a senior fellow at the Center for Strategic and International Studies, writes: "The most knowledgeable analysts and investigators at the CIA and at the FBI believe that their work conclusively disproves Mylroie's claims." Dr. Robert Leiken of the Nixon Center comments on the lack of evidence in her work: "Laurie has discovered Saddam's hand in every major attack on US interests since the Persian Gulf War, including U.S. embassies in Kenya and Tanzania and even the federal building in Oklahoma City. These allegations have all been definitively refuted by the FBI, the National Transportation Safety Board (NTSB) and other investigatory bodies...."

In March 2008, the Pentagon released its study of some 600,000 documents captured in Iraq after the 2003 invasion (see 2008 Pentagon Report). The study "found no 'smoking gun' (i.e., direct connection) between Saddam's Iraq and al Qaeda." Among the documents released by the Pentagon was a captured audio file of Saddam Hussein speculating that the 1993 attack on the World Trade Center had been carried out by Israel or American intelligence, or perhaps a Saudi or Egyptian faction. Saddam said that he did not trust the bomber Yasin, who was in Iraqi custody, because his testimony was too "organized." The Pentagon study found that Yasin "was a prisoner, and not a guest, in Iraq." Mylroie denied that this was proof of Saddam's non-involvement, claiming that "one common purpose of such meetings was to develop cover stories for whatever Iraq sought to conceal."

Improved Security

In the wake of the bombing, and the chaotic evacuation which followed, the World Trade Center and many of the firms inside it, revamped emergency procedures, particularly with regard to evacuation of the building. These policies played a role in evacuating the building during the 2001 terrorist attack which destroyed the towers.

Legal responsibility

The victims of the 1993 World Trade Center bombings sued the Port Authority of New York and New Jersey for damages. A decision was handed down in 2006, assigning liability for the bombings to the Port Authority. The decision declared that the agency was 68 percent responsible for the bombing, and the terrorists bore only 32 percent of the responsibility. In January 2008, the Port Authority asked a five-judge panel of the Appellate Division of the New York State Supreme Court in Manhattan to throw out the decision, describing the jury's verdict as "bizarre". On April 29, 2008, a New York State Appeals Court unanimously upheld the jury's verdict. Under New York law once a defendant is more than 50 percent at fault, he/she/it can be held fully financially liable.

It has been argued that the problem with the apportionment of responsibility in the case is not the jury's verdict, but rather New York's tort-reform-produced state apportionment law. Traditionally courts do not compare intentional and negligent fault. When the Port Authority's very duty was to take care to prevent terrorist attacks, it makes no sense[weasel words] to diminish the Port Authority's liability because a terrorist attack took place. The Restatement Third of Torts: Apportionment of Liability recommends a rule to prevent juries from having to make nonsensical comparisons like the terrorist-Port Authority comparison in this case. However, if a jurisdiction does compare these intentional and negligent torts courts' second-best position is to do just what the NYS Appeals Court did—to uphold all jury apportionments, even those that assign greater, or perhaps far greater, responsibility to negligent than intentional parties.